Gas-burner device and method for operating a gas-burner device

ABSTRACT

A gas-burner device and a method for operating a gas-burner device, includes a conveyor device for conveying a gaseous fuel to a burner and includes a recirculation device for recirculating an exhaust gas quantity produced during the combustion of the fuel to the burner. A sensor device ascertains the composition of the fuel, and the recirculation device is designed to be controlled on the basis of the fuel composition detected by the sensor device.

The invention relates to a gas-burner device according to the preamble of claim 1 and a method for operating a gas-burner device according to the preamble of claim 8.

A gas-burner device of the type mentioned in the introduction is disclosed in the document US 2016/0146455 A1. This gas-burner device consists of a conveying apparatus, for conveying a gaseous fuel to a burner, and a recirculation apparatus, for returning to the burner a quantity of exhaust gas produced during a combustion of the fuel. Expressed in terms of the method, in this solution a gaseous fuel is conveyed by a conveying apparatus to a burner and a quantity of exhaust gas produced during a combustion of the fuel is returned to the burner by a recirculation apparatus. In this solution, a valve (see reference signs 128 and 228) is provided on the recirculation apparatus for adjusting said quantity of exhaust gas.

The object of the invention is to improve a gas-burner device of the type mentioned in the introduction and a method for operating such a gas-burner device. In particular, a gas-burner device which can be used more universally relative to the gaseous fuel used or a more universal method for the operation thereof is intended to be provided.

In terms of the product, this object is achieved by a gas-burner device of the type mentioned in the introduction by the features set forth in the characterising part of claim 1. In terms of the method, this object is achieved by a method for operating such a gas-burner device by the features set forth in the characterising part of claim 8.

In terms of the product, a sensor apparatus is thus provided according to the invention for ascertaining a composition of the fuel, wherein the recirculation apparatus is configured so as to be controlled as a function of the composition of the fuel detected by the sensor apparatus.

In terms of the method, it is provided according to the invention that a composition of the fuel is ascertained by a sensor apparatus and the recirculation apparatus is controlled as a function of the composition of the fuel detected by the sensor apparatus.

In this case, the term “controlled” used for the sake of simplicity in the present context encompasses the two terms “control” and “regulate” which are common in control technology.

In other words, the gas-burner device according to the invention or the method according to the invention for operating such a gas-burner device is thus characterized in that the quantity of exhaust gas returned to the burner is determined as a function of the composition of the fuel. As was surprisingly able to be determined, the result of this is that both natural gas and liquid petroleum gas, for example, and even hydrogen can be burned with a single burner and namely without a further change of components or a re-parameterization.

In terms of the product or in terms of the method, the stipulation that “a sensor apparatus is provided for ascertaining a composition of the fuel” or that “a composition of the fuel is ascertained by a sensor apparatus” means quite generally in this case that the sensor apparatus is suitable for drawing conclusions about the composition of the fuel, selectively directly or indirectly. As will be discussed in more detail below, the sensor apparatus can thus be configured, for example, as a gas chromatograph but also as a temperature sensor for detecting the combustion surface temperature. For example, it is also possible to use a sensor apparatus which measures UV light in order to detect the so-called OH bands and/or CH bands which are produced as an intermediate product during the combustion and from which conclusions can be drawn about the composition of the fuel. In short: the sensor apparatus can be configured very differently; ultimately the composition of the fuel used is to be ascertained or can be ascertained thereby, in order to determine on this basis the quantity of exhaust gas which is actually to be returned for a clean combustion.

Further advantageous developments of the gas-burner device according to the invention or the method according to the invention are found in the dependent claims.

For the sake of completeness, reference is also made to the following documents.

A burner device with a conveying apparatus and a recirculation apparatus is also disclosed in the patent specification DE 39 38 090 C1. In this solution, which however also has no sensor apparatus for ascertaining the composition of the fuel, the two impellers are also located on a common drive shaft and thus cannot be operated independently of one another.

A burner device is also disclosed in the document FR 2 711 224 A1, in which the conveying apparatus and the recirculation apparatus are fixedly connected together.

A heating boiler with two flue gas channels is disclosed in the patent specification DE 693 12 226 T2.

A burner for the combustion of hydrogen is disclosed in the document WO 1995/023315 A1, in which however only a local recirculation is provided in the region of the individual flame jets (flame recirculation).

The gas-burner device according to the invention or the method according to the invention for operating such a gas-burner device is explained in more detail hereinafter with reference to the graphic representation of a preferred exemplary embodiment.

In the schematic drawing

FIG. 1 shows the gas-burner device according to the invention with a sensor apparatus which is arranged upstream of the fuel-air mixing apparatus, when viewed in the direction of flow of the fuel.

The gas-burner device shown in the FIGURE firstly consists in the known manner of a conveying apparatus 1 for conveying a gaseous fuel to a burner 2 and a recirculation apparatus 3 for returning to the burner 2 a quantity of exhaust gas produced during a combustion of the fuel. The conveying apparatus 1 preferably comprises a blower in this case.

Expressed in terms of the method, accordingly a method for operating a gas-burner device is provided in which a gaseous fuel is conveyed by a conveying apparatus 1 to a burner 2 and a quantity of exhaust gas produced during a combustion of the fuel is returned to the burner 2 by a recirculation apparatus 3.

It is thus essential to the gas-burner device according to the invention that a sensor apparatus 4 is provided for ascertaining a composition of the fuel and the recirculation apparatus 3 is configured to be controlled as a function of the composition of the fuel detected by the sensor apparatus 4.

Once again expressed in terms of the method, according to the invention it is provided that a composition of the fuel is ascertained by a sensor apparatus 4 and the recirculation apparatus 3 is controlled as a function of the composition of the fuel detected by the sensor apparatus 4.

Considered in more detail, it is particularly preferably provided that the sensor apparatus 4 is selectively configured as a gas chromatograph, as a gas thermal conductivity sensor, as an ionization sensor, as a UV sensor, as an oxygen sensor and/or as a temperature sensor (in particular a flame temperature sensor).

In this case, when viewed in the direction of flow of the fuel, the gas chromatograph and the gas thermal conductivity sensor are arranged upstream (i.e. in the region upstream of a combustion) and the ionization sensor, the UV sensor, the oxygen sensor and/or the temperature sensor are arranged downstream or on the burner 2 (i.e. in the region of the combustion). The only FIGURE shows schematically the option of a gas chromatograph or a gas thermal conductivity sensor on the fuel supply line. The remaining options are not specifically shown, since they are easily conceivable.

Relative to the above-mentioned UV sensor, it is particularly preferably provided here that this UV sensor is configured to detect OH bands in the wavelength range of 300 nm to 320 nm, preferably 308 nm, and CH bands in the wavelength range of 410 nm to 450 nm, preferably 430 nm (see also https://www.uni.due.de/ivg/rf/forschung/chemilumineszenz.php)

As described in the introduction, each sensor apparatus 4 is suitable for ascertaining the composition of the fuel used.

It is particularly preferably provided here that hydrogen and/or natural gas are or is selectively used as the gaseous fuel.

It is also particularly preferably provided here that, when using pure hydrogen as fuel, a greater quantity of exhaust gas is returned to the burner 2 than when using pure natural gas as fuel.

It is also preferably provided that, when using a mixture of hydrogen and natural gas as fuel, a smaller quantity of exhaust gas is returned to the burner 2 than when using pure hydrogen and a greater quantity of exhaust gas is returned to the burner than when using pure natural gas.

It is also preferably provided that the recirculation apparatus 3 comprises a recirculation valve 3.1 which is preferably and selectively arranged on the connecting line 3.3 (still to be described) and/or connected to a control apparatus 6. Alternatively, expressed in terms of the method: a quantity of exhaust gas returned to the burner 2 is controlled by a recirculation valve 3.1 belonging to the recirculation apparatus 3. As shown in the only FIGURE by the dotted line, the aforementioned control apparatus 6 is configured in terms of data technology to be selectively connected to the conveying apparatus 1, the sensor apparatus 4 and/or (as explained above) to the recirculation apparatus 3 or the (preferably electrically actuatable) recirculation valve 3.1. The conveying apparatus 1 and the recirculation apparatus 3 in each case are preferably controlled individually as a function of the composition of the fuel (preferably by the control apparatus 6).

Moreover, it is also particularly preferably provided that, when viewed in the direction of flow of the fuel, a fuel-air mixing apparatus 5 is arranged upstream of the burner 2, and preferably also upstream of the conveying apparatus 1, as shown. Alternatively, in other words: a fuel-air mixing apparatus 5, which is provided for mixing the gaseous fuel with air, is preferably controlled by the control apparatus 6 as a function of the composition of the gaseous fuel. It is further preferably provided here that this fuel-air mixing apparatus has, in addition to a fuel supply connection 5.1 and an air supply connection 5.2, an exhaust gas supply connection 5.3 which is connected to the recirculation apparatus 3.

It is also preferably provided that the burner 2 (for example—as shown schematically—a cylinder burner) is arranged in a combustion chamber 2.1 with an exhaust gas discharge connection 2.2 and the recirculation apparatus 3 has an exhaust gas connection 3.2 which is connected to the exhaust gas discharge connection 2.2. Finally, the exhaust gas connection 3.2 of the recirculation apparatus 3 is preferably configured so as to be connected to the exhaust gas supply connection 5.3 of the fuel-air mixing apparatus 5 via a connecting line 3.3.

LIST OF REFERENCE SIGNS

-   -   1 Conveying apparatus     -   2 Burner     -   2.1 Combustion chamber     -   2.2 Exhaust gas discharge connection     -   3 Recirculation apparatus     -   3.1 Recirculation valve     -   3.2 Exhaust gas connection     -   3.3 Connecting line     -   4 Sensor apparatus     -   5 Fuel-air mixing apparatus     -   5.1 Fuel supply connection     -   5.2 Air supply connection     -   5.3 Exhaust gas supply connection     -   6 Control apparatus 

1. A gas-burner device comprising a conveying apparatus (1) for conveying a gaseous fuel to a burner (2) and a recirculation apparatus (3) for returning to the burner (2) a quantity of exhaust gas produced during a combustion of the fuel, wherein a sensor apparatus (4) is provided for ascertaining a composition of the fuel and the recirculation apparatus (3) is configured so as to be controlled as a function of the composition of the fuel detected by the sensor apparatus (4).
 2. The gas-burner device according to claim 1, wherein the sensor apparatus (4) is selectively configured as a gas chromatograph, as a gas thermal conductivity sensor, as an ionization sensor, as a UV sensor, as an oxygen sensor and/or as a temperature sensor.
 3. The gas-burner device according to claim 1, wherein the recirculation apparatus (3) comprises a recirculation valve (3.1).
 4. The gas-burner device according to claim 1, wherein, when viewed in the direction of flow of the fuel, a fuel-air mixing apparatus (5) is arranged upstream of the burner (2).
 5. The gas-burner device according to claim 4, wherein the fuel-air mixing apparatus (5) has, in addition to a fuel supply connection (5.1) and an air supply connection (5.2), an exhaust gas supply connection (5.3) which is connected to the recirculation apparatus (3).
 6. The gas-burner device according to claim 1, wherein the burner (2) is arranged in a combustion chamber (2.1) with an exhaust gas discharge connection (2.2) and the recirculation apparatus (3) has an exhaust gas connection (3.2) which is connected to the exhaust gas discharge connection (2.2).
 7. The gas-burner device according to claim 1, wherein the exhaust gas connection (3.2) of the recirculation apparatus (3) is configured so as to be connected to an exhaust gas supply connection (5.3) of a fuel-air mixing apparatus (5) via a connecting line (3.3).
 8. A method for operating a gas-burner device in which a gaseous fuel is conveyed by a conveying apparatus (1) to a burner (2) and a quantity of exhaust gas produced during a combustion of the fuel is returned to the burner (2) by a recirculation apparatus (3), wherein a composition of the fuel is ascertained by a sensor apparatus (4) and the recirculation apparatus (3) is controlled as a function of the composition of the fuel detected by the sensor apparatus (4).
 9. The method according to claim 8, wherein the conveying apparatus (1) and the recirculation apparatus (3) in each case are controlled individually as a function of the composition of the fuel.
 10. The method according to claim 8, wherein selectively hydrogen and/or natural gas are or is used as the gaseous fuel. 